Abstract: Against the contradiction between the growing demand for precise radiotherapy among elderly cancer patients in China and the lack of age-friendly considerations in conventional treatment room design, this study explores an integrated design method for linear accelerator rooms in geriatric hospitals, aiming to develop radiotherapy spaces that balance radiation safety and elderly patient-centered humanistic care. Taking an externally-attached accelerator room in a geriatric hospital in Guangzhou as a case, field measurements, Monte Carlo simulations and BIM collaborative technology were adopted. A rectangular plan of 15.1 m × 14.1 m combined with a Z-shaped maze was designed, with the maze width expanded to 2200 mm. A dual shielding system of "natural soil layer + artificial structure" was formed through the externally-attached layout, and a multi-dimensional age-friendly design framework covering "safety, efficiency, accessibility, cognition, psychology and economy" was constructed.The externally-attached layout reduced the cost of deep foundation pit support by approximately 18%, and the ventilation frequency reached 10.1 times per hour, meeting the specification requirements. The age-friendly design shortened the single core procedure time for patients to ≤15 min, and the ambient radiation level was close to the natural background.The externally-attached layout integrated with age-friendly maze design not only ensures radiation safety but also improves engineering economy and treatment adaptability. The multi-dimensional integrated design framework achieves deep coordination between radiation protection and geriatric care, providing a reproducible and optimizable technical approach for the design of radiotherapy rooms in specialized geriatric hospitals.